FDA Grants Fast Track Designation to 67Cu-SAR-bisPSMA for Prostate Cancer

The FDA has granted fast track designation (FTD) to ⁶⁷Cu-SAR-bisPSMA (Clarity Pharmaceuticals), which is indicated for the treatment of adult patients with prostate-specific membrane antigen (PSMA)-positive metastatic castration-resistant prostate cancer (mCRPC) who have previously received androgen receptor pathway inhibition (ARPI). Data for the FTD was based on preliminary results from the phase 1 and 2a SeCuRE study (NCT04868604), which assessed the safety and efficacy of ⁶⁷Cu-SAR-bisPSMAsafety among individuals with mCRPC.¹

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“This latest FTD will allow us flexibility to develop ⁶⁷Cu-SAR-bisPSMA [for] both pre- and post-chemotherapy in the mCRPC setting, with initial focus on the largest market segment,” Alan Taylor, PhD, Clarity's executive chairperson, said in a news release. “The SECuRE study will also provide invaluable information on the potential of ⁶⁷Cu-SAR-bisPSMA to be combined with enzalutamide [Xtandi; Astellas Pharma] and other ARPIs in the future, creating opportunities for the broader use of ⁶⁷Cu-SAR-bisPSMA in those patients with such high unmet medical need.”¹

According to the American Cancer Institute, an estimated 313,780 new cases of prostate cancer will develop in 2025 among US adults, accounting for around 35,770 deaths.¹ While prostate cancer is usually found early and grows slowly, it remains the second most common cancer diagnosed in men and is the fifth leading cause of cancer death in men globally.²

CRPC is an advanced form of prostate cancer that no longer responds fully to testosterone-lowering treatments. CRPC is indicated by continued growth, such as a rising prostate-specific antigen (PSA) level, despite low testosterone. mCRPC occurs when the cancer becomes hormone-resistant and spreads to other parts of the body, such as lymph nodes, bones, or other organs. mCRPC may be asymptomatic or present symptoms, depending on tumor size and location. Potential signs of mCRPC include urinary problems, pain or blood in urine, fatigue, weight loss, shortness of breath, and bone pain.³

SAR-bisPSMA combines 2 PSMA-targeting agents with Clarity's sarcophagine (SAR) technology. This SAR technology creates a cage-like structure, or chelator, that securely holds copper isotopes and prevents leakage. SAR-bisPSMA is a Targeted Copper Theranostic (TCT) usable with copper-64 for imaging and copper-67 for therapy, according to study authors.¹

The current FTD for ⁶⁷Cu-SAR-bisPSMA follows 2 previously approved FTDs for ⁶⁴Cu-SAR-bisPSMA. The first FTD is for the treatment of suspected metastasis of prostate cancer among individuals who are candidates for initial definitive therapy, and the second is for individuals with biochemical recurrence of prostate cancer following definitive therapy.¹

The ongoing multicenter, single arm, dose escalation SECuRE study with a cohort expansion, aimed to assess the safety and tolerability of ⁶⁴Cu-SAR-bisPSMA and ⁶⁷Cu-SAR-bisPSMA, as well as the efficacy of ⁶⁷Cu-SAR-bisPSMA as a therapy to treat mCRPC. Individuals included in the first 3 cohorts of the dose escalation phase received a single dose of 4 GBq, 8 GBq, and 12 GBq of ⁶⁷Cu-SAR-bisPSMA.⁴

The preliminary results from the SeCuRE study demonstrated that 77% of individuals had bone metastasis and median PSA levels of 112.86 ng/mL at baseline. Additionally, most individuals were heavily pre-treated as 59% received 3 or more prior therapies. Despite this, 73% of participants across all dose cohorts, including the lowest 4 GBq single-dose cohort, experienced PSA reductions. Most PSA increases were observed in the lowest dose cohort. Overall, 45% of participants achieved PSA reductions greater than 50% after a single dose of 67Cu-SAR-bisPSMA. In the higher dose cohorts, nearly 75% achieved PSA reductions greater than 35%, and almost half experienced reductions of 80% or more.^1,4

The study authors noted that no dose limiting toxicities were reported among any of the patients included in the 3 cohorts and no adverse events (AEs) were observed among individuals that received ⁶⁴Cu-SAR-bisPSMA. However, mild dry mouth was the most common AE reported related to ⁶⁷Cu-SAR-bisPSMA.¹

The SECuRE trial is currently evaluating the highest dose cohort, receiving multiple 12 GBq doses of 67Cu-SAR-bisPSMA, with recruitment complete and participants undergoing safety and efficacy follow-up.¹

“The clinical data in both diagnostic and therapeutic indications that we are generating is remarkable, confirming the results that we initially saw in preclinical development. The granting of FTDs by the FDA for 3 distinct indications in prostate cancer that we are aiming to address with this product is testament to the incredible work of our team and collaborators,” Taylor said in a news release.¹

REFERENCES

1. Clarity receives US FDA Fast Track Designation for the treatment of metastatic castration-resistant prostate cancer patients with Cu-67 SAR-bisPSMA. Clarity Pharmaceuticals. News release. Published February 19, 2025. Accessed February 20, 2025. https://www.prnewswire.com/news-releases/clarity-receives-us-fda-fast-track-designation-for-the-treatment-of-metastatic-castration-resistant-prostate-cancer-patients-with-cu-67-sar-bispsma-302379766.html

2. Prostate cancer. Mayo Clinic. News release. Updated February 20, 2025. Accessed February 20, 2025. https://www.mayoclinic.org/diseases-conditions/prostate-cancer/symptoms-causes/syc-20353087

3 Urology Care Foundation. Metastatic Castration-Resistant Prostate Cancer (mCRPC) What You Should Know. Accessed February 20, 2025.

4. 67Cu-SAR-bisPSMA. Clarity Pharmaceuticals. News release. Accessed February 20, 2025. https://www.claritypharmaceuticals.com/pipeline/sar-bispsma/67cu-sar-bispsma/